EP0486255A2 - Metalldichtung - Google Patents

Metalldichtung Download PDF

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Publication number
EP0486255A2
EP0486255A2 EP91310422A EP91310422A EP0486255A2 EP 0486255 A2 EP0486255 A2 EP 0486255A2 EP 91310422 A EP91310422 A EP 91310422A EP 91310422 A EP91310422 A EP 91310422A EP 0486255 A2 EP0486255 A2 EP 0486255A2
Authority
EP
European Patent Office
Prior art keywords
beads
metallic
portions
cylinder bore
bore holes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP91310422A
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English (en)
French (fr)
Other versions
EP0486255A3 (en
EP0486255B1 (de
Inventor
Shigeru Kawaguchi
Masahiko Miura
Kenji Kubouchi
Hiroshi Uemura
Kunitoshi Inoue
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Gasket Co Ltd
Original Assignee
Nippon Gasket Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Priority claimed from JP30629590A external-priority patent/JP2930699B2/ja
Priority claimed from JP03156189A external-priority patent/JP3086008B2/ja
Application filed by Nippon Gasket Co Ltd filed Critical Nippon Gasket Co Ltd
Publication of EP0486255A2 publication Critical patent/EP0486255A2/de
Publication of EP0486255A3 publication Critical patent/EP0486255A3/en
Application granted granted Critical
Publication of EP0486255B1 publication Critical patent/EP0486255B1/de
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/06—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/08—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with exclusively metal packing
    • F16J15/0818—Flat gaskets
    • F16J15/0825—Flat gaskets laminated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/06—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/08—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with exclusively metal packing
    • F16J15/0818—Flat gaskets
    • F16J2015/0837—Flat gaskets with an edge portion folded over a second plate or shim
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/06—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/08—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with exclusively metal packing
    • F16J15/0818—Flat gaskets
    • F16J2015/0843—Flat gaskets with an edge portion folded over the plate itself
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/06—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/08—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with exclusively metal packing
    • F16J15/0818—Flat gaskets
    • F16J2015/085—Flat gaskets without fold over

Definitions

  • This invention relates to a metallic gasket for use in sealing a clearance between the opposed surfaces to be joined together of a cylinder head and a cylinder block, and a method of manufacturing the same.
  • a gasket formed out of a metal has been used to seal a clearance between opposed surfaces to be joined together of structural members of an engine, such as a cylinder head and a cylinder block.
  • Metallic gaskets which are developed for the purpose of improving their performance of sealing the high-pressure portions to be sealed, i.e. the peripheral portions of through bores, and which include a metallic gasket provided with a layerofa soft metal on the top portions of the beads (refer to, for example, Japanese Utility Model Laid-open No. 145665/1985), and a metallic gasket provided with a spacer (refer to, for example, Japanese Utility Model Laid-open No. 16459/1986), have been proposed.
  • top portions are formed on the beads provided on the peripheral portions of through bores so as to increase the height of the beads.
  • a metallic gasket is tightened between a cylinder head and a cylinder block to bring the opposed surfaces to be combined together of the structural members into pressure contact with each other, the metallic gasket is compressed more tightly by as much as the increase, which is ascribed to the provision of the layer of a soft metal or a spacer, of the height of the beads. Therefore, the improvement in the performance of the metallic gasket of sealing the surfaces combined of the portions of the structural members which are around the cylinder bore holes is expected. If the padding is done on such a metallic gasket by using a soft material, a local pressure imparted to the metallic gasket will be scattered, and the improvement of the sealing performance of the metallic gasket or the protection of the beads will be attained.
  • a metallic gasket other than these prior art metallic gaskets is also known, in which grommets are attached to the circumferential portions, which are provided with beads projecting therefrom and constitute pressure-contacting portions to be sealed, of cylinder bore holes (refer to, for example, Japanese Patent Laid-open Nos. 101574/1988 and 149479/1988). Even when the grommets attached to the circumferential portions of the cylinder bore holes in this metallic gasket are exposed to a fluid of high temperature and pressure, such as a combustion gas, the sealing performance of the gasket is not deteriorated. Even if the leakage should occur in the grommets, the beads prevent the fluid from flowing out.
  • this metallic gasket has a function of correcting the imperfect alignment of the opposed surfaces to be combined in addition to the fluid sealing function of the beads
  • the operation for attaching grommets to the circumferential portions of the cylinder bore holes involves troublesome work, such as the manufacturing of grommets, the fitting of the grommets around the circumferences of the cylinder bore holes and the deformation-controlling of the grommets, and causes the manufacturing cost to increase.
  • Japanese Patent Laid-open No. 101573/1988 discloses a metallic gasket shown in Figs. 18 and 19.
  • This metallic gasket 18 is adapted to seal the clearance between the opposed surfaces to be combined of a cylinder head 23 and a cylinder block 24, and provided with a bead 21 projecting from the portion which constitutes a pressure-contacting surface to be sealed, and which is around a cylinder bore hole 19, and a seal member 22 in a valley portion 20 formed in the bead 21.
  • a clearance is formed in the part of the valley portion 20 in the bead 21 which is around the seal member 22, so that the seal member 22 can be deformed elastically at large when the opposed surfaces to be combined are tightened.
  • the number of sealing contact portions with respect to the opposed surfaces to be combined on both sides of the metallic gasket 18 does not increase in the positions which are spaced differently away from the cylinder bore holes 19 in the radial direction thereof.
  • the seal members 22 can be provided unitarily with the metallic gasket 18 but that unitarily combining the seal members 22 with the metallic gasket 18 by using a bonding agent or heat will probably take much time since the valley portion 20 in the bead 21 in a free state in a stage in which the gasket has not yet been tightened has a considerably wide clearance.
  • a primary object of the present invention is to solve these problems, and provide a simply constructed metallic gasket capable of correcting the imperfect alignment of the opposed surfaces to be combined, when a cylinder block and a cylinder head in an engine are tightened and fixed to each other via a single plate type elastic metallic body having beads and folded portions; practically offsetting strain, even if it should occur between adjacent cylinder bore holes due to the bend of the cylinder head, by the elastic metallic body to prevent the sealing effect thereof from decreasing, a high-temperature and high-pressure combustion gas which causes the beads to be corroded and soiled from entering the clearance between the opposed surfaces combined, and even a large fluctuating load stress which occurs in the portions of the cylinder head which have the lowest rigidity from causing permanent strain and cracks to occur in the beads; and having looped seal members formed in the portions as well of the elastic metallic body which are other than the bead-carrying portions thereof, and a method of manufacturing such metallic gaskets.
  • This metallic gasket has, in order to achieve this object, a plate type elastic metallic body, cylinder bore holes made in the elastic metallic body, beads formed so that they are spaced radially outward from and extend along the circumferences of the cylinder bore holes, and folded portions formed by turning back the portions of the elastic metallic body which are on the radially outer side of the beads around the cylinder bore holes toward the ridge portions of the beads, the folded portions of the elastic metallic body being molded to a predetermined thickness and heat treated.
  • the quantity of strain occurring in the cylinder head during combustion cycles of the engine i.e. the repetition of the suction stroke, compression stroke, expansion stroke and exhaust stroke, especially, the repetition of expansion stroke is minimized.
  • the number of looped seal portions between the opposed surfaces to be combined of the above-mentioned structural members is increased, the tightening force of the structural members is supported in a divided manner, so that the total compression of the beads is prevented owing to the presence of the folded portions.
  • This enables the fluctuating load stress, which occurs at the time of the starting, rotation and stopping of the engine, to be reduced. Accordingly, this serves to prevent the occurrence of permanent strain and cracks in the beads, and improve the durability of the beads.
  • the folded portions are formed integrally with the gasket body, they are not displaced or irregularly compressed when the gasket is used by being tightened.
  • Another primary object of the present invention is to provide a metallic gasket consisting of a single plate tape elastic metallic body adapted to be interposed between a cylinder block and a cylinder head in an engine and fixed by being tightened, characterized in that the metallic gasket has on the elastic metallic body beads formed so that they are spaced radially outward from and extend along the circumferences of cylinder bore holes made in the elastic metallic body, folded portions formed by turning back the portions of the metallic body which are around the cylinder bore holes and positioned on the innerside of the beads, and regulating plates consisting of a metallic material and laminated on the portions of the elastic metallic body which are spaced from the folded portions and on the radially outer side of the cylinder bore holes and on the projecting surfaces of the beads for the purpose of regulating the strength of the elastic metallic body.
  • this metallic gasket is capable of increasing the strength of the beads by the regulating plates, and the rate of offsetting the imperfect alignment of the beads, reducing the height of the beads by at least a level corresponding to the thickness of the regulating plates, so that the beads can be protected against a high surface pressure imparted thereto, and being formed to a simple structure which can prevent the beads from being totally compressed.
  • the sealing pressure applied to the cylinder head and cylinder block therefore increases by a level corresponding to the increased portion owing to the regulating plate of the thickness of the gasket body, whereby a difference between the thickness of the portions of the elastic metallic body which are in the regions of the folded portions and that of the portions of the elastic metallic body which are in the regions on the radially outer side of the beads can be regulated.
  • the height of the beads can be reduced by at least a level corresponding to the thickness of the regulating plates, and the stress occurring in the beads when the metallic gasket is tightened can therefore be further reduced. This enables the total compression of the beads to be prevented, and the durability of the beads to be improved.
  • the increase of the number of the looped seal portions enables a fluctuating load, which occurs due to the repetition of the combustion cycles of the engine, to be supported in a shared manner owing to the synergistic effect of the increased seal portions and the elimination of the irregularity of the opposed surfaces to be combined, so that the quantity of strain occurring in the cylinder head is minimized.
  • the bead-carrying portions of the elastic metallic gasket are doubly formed owing to the regulating plates laminated thereon, the height of the beads can be reduced by at least a level corresponding to the thickness of the regulating plates owing to the provision thereof.
  • the total compression of the beads can be prevented by the folded portions, and the regulating plates reinforce the elastic metallic body. Accordingly, the fluctuating load stress occurring in the beads at the time of starting, rotation and stopping of the engine decreases, and the occurrence of permanent strain and cracks in the beads can be prevented.
  • this metallic gasket In this metallic gasket, a difference in height corresponding to the thickness of the elastic metallic body thereof occurs between the folded portions and the regions of the radially outer side of the beads. If such a difference in height is not smaller than a required level, the deformation occurring between the cylinder head and cylinder block cannot be offset, or the thickness of the gasket has to be determined on the basis of the quantity of deformation occurring between the opposed surfaces to be combined.
  • this metallic gasket has regulating plates laminated on the elastic metallic body, the difference in height referred to above can be set to an arbitrary level, and the bearing factors of the folded portions and beads around the cylinder bore holes, and the portions of the gasket body which are around the water holes and oil holes can be regulated properly.
  • the beads on the elastic metallic body of this gasket are formed cross-sectionally arcuately along the whole circumference of the cylinder bore holes, or can be formed cross-sectionally arcuately at the top portions of the parts of the beads which extend between adjacent cylinder bore holes, and cross-sectionally flat projecting state at the top portions of the parts of the beads which are other than the parts thereof which extend between adjacent cylinder bore holes.
  • the folded portions are formed to substantially the same thickness along the whole circumference of the cylinder bore holes, or they are formed to a larger thickness at the parts thereof which are between adjacent cylinder bore holes and to smaller thickness at the parts thereof which are other than the parts thereof which are between adjacent cylinder bore holes. Therefore, when the cylinder head, which has a comparatively low rigidity as compared with the cylinder block, has a plurality of ports, the folded portions are able to effectively correct the flexural deformation of the material constituting the walls of adjacent cylinder bore holes.
  • the extent to which the flaps of the folded portions are extended can be set arbitrarily unless these flaps do not overlap the beads on the elastic metallic body. Consequently, when the gasket is designed, the distribution of bearing factors of the beads and folded portions can be regulated.
  • the thickness of the parts of the folded portions which are between adjacent cylinder bore holes is set larger than that of the parts thereof which are other than the parts thereof which are between adjacent cylinder bore holes with the cylinder head, the rigidity of which is comparatively low as compared with that of the cylinder block, having a plurality of ports, the flexural deformation of the material constituting the wall of adjacent cylinder bore holes can be corrected effectively.
  • Another object of the present invention is to provide a metallic gasket having thickness regulating auxiliary metallic plates laminated on the portions of the elastic metallic body which are spaced from and on the radially outer side of the beads, in such a manner that the surfaces of these portions on which the auxiliary plates are laminated are on the same side as the projecting surfaces of the beads.
  • auxiliary metallic plates the thickness of which is smaller than that of the elastic metallic body are laminated on the portions of the elastic metallic body which are exclusive of the cylinder bore holes, and which are spaced from and on the radially outer side of the beads, in such a manner that the surfaces of these portions on which the auxiliary plates are laminated are on the same side as the projecting surfaces of the beads, whereby the difference in height mentioned above can be regulated.
  • Still another object of the present invention is to provide a metallic gasket capable of regulating a difference in height between the folded portions and beads when the height of the folded portions is smaller than that of the beads by a level not higher than a required level, by inserting soft members in the portions to be folded and then folding the flaps of these portions back.
  • the thickness of the soft members can be changed by changing the folding compressive force when the soft members are inserted in the portions to be folded, so as to change the degree of deformation of the soft members.
  • the soft members can be formed so that the portions thereof in the parts of the folded portions which are between adjacent cylinder bore holes, and which have a large thermal load, has a larger thickness with the portions thereof in the parts of the folded portions which are other than the mentioned parts thereof having a smaller thickness, whereby the soft members can be set capable of withstanding a thermal load.
  • the soft members can also be so formed that they are inserted in the parts of the folded portions which are between the cylinder bore holes, and not provided in the other parts thereof. If the difference in height referred to above is set to a proper level, the quantity of strain of the cylinder head occurring at the time of starting, rotation and stopping of the engine is minimized, and the fluctuating load stress based on the strain can also be reduced. This serves to prevent the occurrence of permanent strain and cracks in the beads, and improve the durability of the beads.
  • a further object of the present invention is to provide a metallic gasket in which an elastic metallic body is coated at its both surfaces with a non-metallic material, such as a heat and oil resisting rubber or resin to avoid direct metal-to-metal contact between the elastic metallic body, cylinder head and cylinder block, and enable the corrosion resistance, durability and strength of the corrosive combustion gas-exposed metallic surfaces to be secured, and the sealing function of the gasket to be fully displayed and secured with respect to the uneven processed surfaces of the cylinder head and cylinder block.
  • a non-metallic material such as a heat and oil resisting rubber or resin
  • a further object of the present invention is to provide a metallic gasket in which the folded portions provided on the elastic metallic body are formed so that the thickness of the parts of the folded portions which are between adjacent cylinder bore holes becomes larger with that of the parts thereof which are other than the parts between adjacent cylinder bore holes becoming smaller, to enable the thicker parts of the folded portions to effectively offset the flexure which is liable to occur in the largest scale in the parts of the elastic metallic body which are between adjacent cylinder bore holes due to the bend of the cylinder head, the lowering of the sealing effect of the gasket, and the corrosion and soiling of the beads on the elastic metallic body which are ascribable to the entry of a high-temperature and high-pressure combustion gas to be prevented, the distribution of bearing factor of the elastic metallic body to be corrected properly by increased thickness of the metallic body at the folded portions thereof, the bearing factor of the folded portions and that of the beads to be balanced, and the bearing factor of the folded portions around the cylinder bore holes and those of the beads and the portions of the gasket body which are around the water holes and oil holes
  • Another object of the present invention is to provide a method of manufacturing metallic gaskets, consisting of the steps of forming cylinder bore holes in a metallic plate, molding beads on the portions of the metallic plate which are spaced radially outward from and extend around the cylinder bore holes, folding back the portions of the metallic plate which are around the cylinder bore holes in the radially outward direction so as to form folded portions, applying a compressive force to the folded portions so as to mold the folded portions to a preset thickness, and subjecting the metallic plate on which the folded portions have been formed to a heat treatment for regulating the hardness of the metallic plate to a proper level, to produce an elastic metallic gasket body.
  • the folded portions can be formed by a simple folding operation, and the thickness of these portions can be regulated freely to a desired level during a compression molding of the thickness of the folded portions carried out after the metal plate folding operation. Namely, it is possible not only to set the thickness of the folded portions to a uniform level but also to regulate the thickness of a certain part of even a folded portion, which is formed around the same cylinder bore hole, to a level different from that of the other part thereof.
  • the thickness of the folded portions can be set large taking the flexure of the cylinder into consideration, and in the portion of the gasket which is farther away from these narrowly spaced portion, the thickness of the folded portions can be set gradually smaller or to a predetermined low level.
  • a soft metallic plate as a raw material is subjected to the formation of beads to make holes, which are smaller than the cylinder bore holes in a complete product, and the portions of the resultant soft metallic plate which are around such small holes to a bending process to form cylinder bore holes, and also to a folding process to form folded portions. These folded portions are then compression molded to regulate the thickness thereof, and heat treated to obtain an elastic metallic gasket body.
  • the metallic plate is subjected to bending while it is soft, and no additional processes, such as cutting are not required. Therefore, the processing cost is low, and a metallic gasket having desired hardness and thickness can be obtained after a heat treatment has been completed.
  • Still another object of the present invention is to provide a method of manufacturing metallic gaskets, consisting of the steps of forming cylinder bore holes in a metallic plate, molding beads on the portions of the metallic plate which are spaced radially outward from and extend around the cylinder bore holes, attaching soft metallic plates to the portions of the resultant metallic plate which are around the cylinder bore holes and folding the substrate metallic plate radially outward so as to form folded portions, applying a compressive force to the folded portions so as to mold the folded portions to a preset thickness, and subjecting the substrate metallic plate on which the folded portions have been formed and the soft metallic plates to a heat treatment for regulating the hardness of the metallic plates to proper levels, to produce an elastic metallic gasket body.
  • the hardness of the metallic gasket is regulated in this metallic gasket manufacturing method by carrying out a heat treatment step after a compression molding step has been finished, the hardness can be set freely to a desired level.
  • a metallic gasket shown in Fig. 1 is adapted to seal a clearance between the opposed surfaces to be combined of structural members, and used to seal, for example, the opposed surfaces to be combined of a cylinder head and a cylinder block (neither of which are shown in the drawing) of a four-cylinder engine.
  • the embodiments which will be described hereunder is not limitedly applied to a four-cylinder engine but they can, of course, be applied to, for example, a straight-type six-cylinder engine or a V-type six-cylinder engine.
  • This metallic gasket is produced out of a single elastic metallic plate 1 consisting, for example, of a material to be precipitation hardened, such as SUS630 and SUS631, a material to be nitrided, such as SUS304, SUS301 or a SK material (SK1-SK7), a material to be hardened and tempered, such as SUS420J 2 and SUS440A, or a material to be solid solution heat treated, such as a metal material including titanium alloy and aluminum alloy, any one of these materials being formed to a thickness t of, for example, 0.2 mm - 0.3 mm, the hardness of the material before subjected to the formation of beads being, for example, not higher than Hv 200.
  • a material to be precipitation hardened such as SUS630 and SUS631
  • a material to be nitrided such as SUS304, SUS301 or a SK material (SK1-SK7)
  • SK1-SK7 SK material
  • hardness of these materials which have been heat treated are as follows.
  • SUS304, SUS301 or SK materials (SK1-SK7) were nitrided
  • the hardness of SUS304 and SUS301 was not higher than Hv 200 (surfaces only) before they were heat treated, and not lower than Hv 500 after heat treated
  • the hardness of SX materials (SK1-SK7) was not higher than Hv 200 before they were heat treated, and not lower than Hv 500 after heat treated.
  • SUS630 and SUS631 were precipitation hardened, the hardness thereof was not higher than Hv 200 before they were heat treated, and not lower than Hv 350 after heattreated.
  • the elastic metallic plate 1 of this metallic gasket is provided with four holes corresponding to four cylinders, i.e. cylinder bores formed in a cylinder block, which holes are cylinder bore holes 2A, 23, 2C, 2D (when these cylinder bore holes are generally referred to, they are designated by a reference numeral 2).
  • the elastic metallic plate 1 constituting the metallic gasket is also provided with a plurality of water holes through which cooling water is passed, oil holes and oil return holes through which an oil is passed, knock holes and rivet holes. Since these holes are associated with the techniques known in the technical field of metallic gaskets, the descriptions thereof are omitted in this specification.
  • the upper and lower surfaces of the metallic gasket are coated with a non-metallic material, such as heat and oil resisting rubber (for example, fluororubber) and a resin, to a thickness of, for example around 10 ⁇ - 50 ⁇ (not shown), the metal-to-metal contact of the gasket with the cylinder head and cylinder block can be avoided, and the corrosion resistance, durability and strength of the metallic gasket can be secured. Even when the mechanically processed surfaces of the metallic gasket are uneven, a film of such a non-metallic material covers the uneven surfaces to form excellent surfaces, and this enables the sealing function of the metallic gasket to be satisfactorily displayed.
  • a non-metallic material such as heat and oil resisting rubber (for example, fluororubber) and a resin
  • Fig. 2 is a sectional view of a boundary portion between adjacent cylinder bore holes 2A, 2B in the elastic metallic plate 1 taken along a line connecting the centers of these holes 2A, 2B, i.e. a sectional view of the portion of the elastic metallic plate 1 which is between cylinder bore holes 2.
  • the boundary portions between the other adjacent cylinder bore holes are also formed to have identical cross section as a matter of course.
  • Fig. 3 is a sectional view of the metallic gasket taken along the line connecting the cylinder bore hole 2A and an end portion, i.e. an edge portion of the elastic metallic plate 1.
  • the portion of the metallic plate 1 which is between the cylinder bore hole 2D on the opposite side of the hole 2A and the relative edge portion of the metallic plate 1 is also formed to have an identical cross section. Not only these portions but also the portions of the elastic metallic plate which are around the cylinder bore holes 2 except the regions thereof between the same holes 2 are also formed to have an identical cross section as a matter of course.
  • the portions of the elastic metallic plate 1 constituting the metallic gasket which are close to and around the cylinder bores 2 are provided with cross-sectionally cone-shaped beads 4 formed concentrally with and annularly surround the cylinder bore holes 2 (when the beads are generally referred to, they are designated by a reference numeral 4).
  • each bead 4 starts in a position which is a predetermined distance L 2 away from the inner circumferential edge of a cylinder bore hole 2, for example about 2.9 mm, and extends in a radial direction so that the bead 4 has a predetermined width L 3 of about 2 mm, the height H of the bead 4 being 0.2 - 0.25 mm.
  • a distance L 1 between adjacent cylinder bore holes 2 is, for example, about 7.8 mm.
  • a bead 4A around the cylinder bore hole 2A and a bead 4B around the cylinder bore hole 2B are piled up at the adjoining portions thereof to be formed into one bead 4. These portions of adjacent beads 4 may be formed so as to be spaced from each other by a very short distance without lying one upon the other.
  • folded portions 5A, 5B are formed so that the folded portions do not lie on the radially inner parts of the bead 4 (when the folded portions are generally referred to, they are designated by a reference numeral 5).
  • the width L 4 of each folded portion is, for example, about 2.5 mm.
  • the metallic gasket according to the present invention has the above-described construction, and it can be manufactured through the following steps.
  • various kinds of holes including cylinder bore holes are formed in a metallic plate of a predetermined thickness t.
  • Beads 4 are then molded at the portions of the metallic plate which are spaced radially outward from and extend along the circumferences of the cylinder bore holes 2.
  • the portions of the metallic plate which are around adjacent cylinder bore holes 2 are folded in the radially outward direction with respect to the holes 2 to form folded portions 5.
  • the thickness of the folded portions 5 thus formed is 2t.
  • the metallic plate on which the folded portions 5 have been formed is heat treated so as to regulate the hardness of the metallic plate, whereby an elastic metallic plate 1 is obtained.
  • the elastic metallic plate 1 constituting a folded portion-carrying metallic gasket is heat treated in this final step so that the hardness thereof becomes, for example, not lower than Hv 350.
  • the rigidity of a cylinder head is low as compared with that of a cylinder block.
  • the portions of a metallic gasket which are between adjacent cylinder bore holes 2 are liable to be strained most largely due to fluctuations in load in the explosion and expansion strokes in the combustion cycle of the engine. Therefore, the sealing function of the metallic gasket tends to be deteriorated most significantly at these portions.
  • the precompression compression carried out in advance of the compression for combining the opposed surfaces of the cylinder head and cylinder body
  • the precompression is carried out so that, if the thickness of the metallic plate is set to the thickness 2t i of the part between adjacent cylinder bore holes 2 becomes smaller than that 2t of a folded portion of the metallic plate by a, and the thickness 2t 2 of the parts which are other than the parts between adjacent cylinder bore holes 2 is smaller than that 2t of a folded portion by ⁇ .
  • the thickness 2t i of the part of a folded portion which is between adjacent cylinder bore holes in a region a between the same holes is set to, for example, 0.15 mm, and this thickness gradually decreases in the regions extending on both sides of the region a, the thickness 2t 2 of the parts of the folded portion which are in the area other than the area between adjacent bores 2 in the regions c extending arcuately on both sides of the regions being set to, for example, 0.12 mm.
  • the values of both a and ⁇ can be changed in accordance with the position around the cylinder bore hole 2 as shown in Figs. 8 and 9.
  • auxiliary metallic plates 8 having a thickness t 4 , which is smaller than that t of the elastic metallic plate 1, are attached to the surfaces, which are on the same side as those of the top ends of the projecting portions of the beads 4, of the parts on the radially outer side of the beads 4.
  • the auxiliary metallic plates 8 are provided for the purpose of regulating the difference in thickness between the portions of the metallic plate which are around the cylinder bore holes 2 and those thereof which are on the radially outer side of the beads 4.
  • the auxiliary metallic plates 8 are provided on the flat portions of the surface on the same side as the top ends of the projecting portions of the beads 4 so as to reduce the difference in height between the folded portions 5 and the parts of the metallic plate which are on the radially outer side of the beads 4.
  • soft metallic plates 7A, 7B (when they are generally reffered to, they will be designated by a reference numeral 7) of a thickness t 3 of, for example, 100-200 ⁇ are held in folded portions 5. Therefore, the thickness of the folded portions 5 on an elastic metallic plate 1 which has been precompressed is 2t + t 3 - a at the parts thereof which are between cylinder bore holes 2, and 2t + t 3 - ⁇ at the parts thereof which are around the cylinder bore holes but not between the cylinder bore holes 2.
  • the metallic gasket according to the present invention has the above-described construction, and can be manufactured through the following steps.
  • This method of manufacturing metallic gaskets is identical with the metallic gasket manufacturing method in the previously-described embodiment except that the former has a step of inserting soft metallic plates 7 in the folded portions 5. Therefore, only the step that is different from those in the previously-described embodiment will be described.
  • a step of inserting soft metallic plates 7 in the folded portions 5 is added to a step of bending the portions of a metallic plate which are around the cylinder bore holes 2 in the radially outward direction so as to form folded portions 5.
  • a compressive force is then applied to the folded portions 5 in which the soft metallic plates 7 have been held so as to mold the folded portions to a preset thickness.
  • the metallic plate on which the folded portions have been formed and the soft metallic plates 7 inserted in the folded portions 5 are heat treated to regulate the hardness thereof.
  • the soft metallic plates 7 are provided for the purpose of regulating a difference in thickness between the parts of the folded portions around the cylinder bore holes 2 and the parts thereof which are on the radially outer side of the beads 4.
  • these soft metallic paltes 7 are provided on the surfaces of the folded portions which are on the same side of the projecting end surfaces of the beads 4 so as to increase the difference in height between the folded portions 5 and the portions of the metallic plate which are on the radially outer side of the beads 4.
  • the metallic gasket is inserted between the cylinder head and cylinder block.
  • the beads 4 provided around the positions close to the cylinder bore holes 2 in the elastic metallic plate 1 form looped seal portions linearly contacting (before a load is applied) or narrowly surface contacting (after a load is applied) the joint surface of the cylinder head.
  • the sealing pressure of the folded portions 5, which form looped seal portions with respect to the opposed surfaces to be combined of the cylinder block and cylinder head, against these cylinder head and cylinder block increases by a level corresponding to the increase in the thickness of the plate, and these two-step looped seal portions prevent the high-temperature and high-pressure combustion gas from flowing along the circumferences of the cylinder bore holes 2 and leaking from the opposed joint surfaces of the cylinder head and cylinder block.
  • the folded portions 5 in addition to the beads 4 also contact the opposed joint surfaces to support the tightening force in a shared manner, so that the total compression on the beads 4 is alleviated by as much as a portion shared by the folded portions 5, whereby a load stress occurring in the beads 4 is reduced.
  • FIG. 10 A further embodiment of the metallic gasket according to the present invention will now be described with reference to Figs. 10, 11, 12, 13 and 14. Since the construction of this embodiment is substantially identical with that of the metallic gasket shown in Fig. 1 except that regulating plates 6 consisting of metallic plates are laminated on the elastic metallic plate 1, the duplication of descriptions will be omitted by designating the same parts by the same reference numerals.
  • the thickness 2t i of the part of a folded portion which is between adjacent cylinder bore holes in a region a between the same holes is set to 0.37 mm, and this thickness decreases gradually in the regions b extending on both sides of the region a, the thickness 2t 2 of the parts of the folded portion which are in the regions c extending arcuately on both sides of the regions b being set to, for example, 0.32 mm, as shown in Figs. 8 and 9.
  • the elastic metallic plate 1 on which the folded portions 5 have been formed is heat treated to regulate the hardness thereof.
  • the hardening of the metallic plate is done so that the hardness thereof which is not higher than Hv 200 prior to the formation of the beads 4 attains a level, which corresponds to the kind of the material of the elastic metallic plate 1, after a heat treatment has been finished.
  • This embodiment is characterized in that the regulating plates 6 consisting of metallic plates are laminated on the beads 4 on the elastic metallic plate 1 so as to reinforce the same plate 1 and also increase the strength of the beads 4.
  • the plate thickness regulating plates 6 are laminated on the surfaces, which are on the same side of the projecting end surfaces of the beads 4, of the portions of the metallic plate which correspond to the beads 4 around the cylinder bore holes 2 and the portions farther away therefrom, i.e. the surfaces of the portions of the metallic plate which correspond to the radially outer side of the holes 2 inclusive of the beads 4.
  • the part thereof which is farther away from the bead 4 with respect to both the cylinder bore holes 2A, 2B is the bead 4 itself.
  • the regulating plates 6 are laminated on the beads 4 only.
  • the regulating plates 6 are formed out of a hard material (Hv 350-500), such as SUS301 or SUS304, and have a thickness t 4 (for example, 0.10-0.200 mm) which is smaller than that t (for example, 0.2-0.3 mm) of the metallic gasket.
  • the regulating plates 6 are provided mainly for the purpose of regulating a difference between the thickness of the parts of the elastic metallic plate 1 constituting the metallic gasket which are around the cylinder bore holes 2, i.e the folded portions 5 and that of the parts of the metallic plate 1 which are on the radially outer side of the beads 4.
  • the regulating plates 6 are laminated on the projecting end surfaces of the beads 4 so as to minimize the difference in height between the folded portions 5 and the parts of the metallic plate which are farther away from or on the radially outer side of the beads 4. Since the regulating plates 6 consist of the above-mentioned hard material, the strength of the laminated portions including the beads 4 can be increased, and the regulating plates 6 can be provided with the function of protecting the metallic plate against the surface pressure occurring when the beads 4 contact the opposed surfaces to be combined of the cylinder head and cylinder block. As shown in Fig.
  • the metallic gasket is deformed so that the portion thereof which is around the hole 3 is recessed slightly (or in the shape of a mountain) from the other planar portion and concentrically with the hole 3, and such a recessed portion enables a sealing effect to be obtained around the hole 3 when the metallic gasket is tightened.
  • the beads 4 provided on the portions of the elastic metallic plate 1 which are close to and around the cylinder bore holes 2 contact the joint surface of the cylinder head to form looped seal portions.
  • the folded portions 5 form looped seals at the inner side of the looped seal portions based on the beads 4, with respect to the opposed surfaces to be combined of the cylinder block and cylinder head, and the sealing pressure applied to the cylinder head and cylinder block becomes hgiher by a level corresponding to an increase in the thickness of the metallic gaslet. Owing to such two-step looped seal portions, the leakage of a high-temperature and high-pressure combustion gas from the cylinder bore holes 2 to the opposed joint surfaces of the cylinder head and cylinder block can be prevented.
  • the tightening force is supported in a joint manner on the beads 4 and folded portions 5. Furthermore, since the beads 4 have regulating plates 6 laminated thereon, the height of the beads 4 can be reduced by a level corresponding to the thickness of the regulating plates 6. Accoridngly, the stress occurring in the beads 4 during a tightening operation is further reduced, and the total compression is prevented. Even if the minimized repeated stress mentioned above is imparted to the metallic gasket due to the fluctuation of load during the operation of the engine, the occurrence of permanent strain and cranks in the beads 4 can be prevented since the load stress occurring in the beads 4 is reduced.
  • the thickness of the folded portions 5 on an elastic metallic plate which has been precompressed is 2t + t 3 - a at the parts thereof which are between cylinder bore holes 2, and 2t + t 3 - ⁇ at the parts thereof which are around the cylinder bore holes but not between the cylinder bore holes 2. Since ⁇ has a value larger than that of a, the thickness (2t + t 3 - a) of the parts of the folded portions which are between the cylinder bore holes 2 becomes larger than that (2t + t 3 - (3) of the parts thereof which are around the cylinder bore holes 2 but not between the cylinder bore holes 2.
  • the soft metallic plate 7 can be modified variously. Namely, the values of a and ⁇ can be changed in accordance with the position of the portion of the metallic gasket which is around a cylinder bore hole as shown in Figs. 8 and 9.
  • the soft metallic plates 7 may be provided on the whole circumferential areas of the folded portions 5, or formed so that the thickness of the soft metallic plates 7 is larger at only the parts thereof that are between adjacent cylinder bore holes 2, and smaller at the parts thereof which are other than the parts between adjacent cylinder bore holes 2, or provided on only the parts thereof which are between adjacent cylinder bore holes 2.
  • the soft metallic plates 7 are inserted in the folded portions 5 in the step of forming the folded portions 5, after the regulating plates 6 have been laminated on the elastic metallic plate 1. A compressive force is then applied to the folded portions 5 so as to mold the same to a preset thickness. Finally, the elastic metallic plate 1 on which the folded portions 5 have been formed and the soft metallic plates 7 held in the folded portions 5 are heat treated to regulate the hardness thereof.
  • the soft metallic plates 7 are provided for the purpose of regulating a difference in thickness between the parts of the folded portions around the cylinder bore holes 2 and the parts thereof which are on the radially outer side of the beads 4. For example, when the thickness of the folded portions decreases largely at the parts thereof which are around the cylinder bore holes 2 due to the precompression of the folded portions, these soft metallic plates 7 are laminated on the surfaces of the folded portions which are on the same side of the projecting end surfaces of the beads 4, and held in the folded portions 5,whereby a difference in height between the folded portions 5 and the portions of the metallic plate which are on the radially outer side of the beads 4 is increased.
  • the embodiment shown in Fig. 17 is identical with the second embodiment except that it includes an example of beads 4, in which the shape of the portions of the beads 4 which are around the cylinder bore holes 2 but not between adjacent cylinder bore holes is modified.
  • the portions of the beads 4 which are in such areas, and which have a radial width of d are flattened at the projecting top parts thereof, and the spring constant of these portions is set smaller correspondingly. Since the shape of the portions of the heads 4 which are between adjacent cylinder bore holes 2 is identical with that of the corresponding portions in the previously-described embodiment, the duplication of descriptions will be omitted.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Gasket Seals (AREA)
EP19910310422 1990-11-14 1991-11-12 Metalldichtung Expired - Lifetime EP0486255B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP30629590A JP2930699B2 (ja) 1990-11-14 1990-11-14 金属製ガスケット及びその製造方法
JP306295/90 1990-11-14
JP03156189A JP3086008B2 (ja) 1991-05-31 1991-05-31 金属製ガスケット
JP156189/91 1991-05-31

Publications (3)

Publication Number Publication Date
EP0486255A2 true EP0486255A2 (de) 1992-05-20
EP0486255A3 EP0486255A3 (en) 1992-12-02
EP0486255B1 EP0486255B1 (de) 1996-10-23

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Family Applications (1)

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EP (1) EP0486255B1 (de)
DE (2) DE69122838T2 (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0528698A1 (de) * 1991-08-21 1993-02-24 NIPPON GASKET COMPANY Ltd. Metalldichtung und Verfahren zu deren Herstellung
EP0531076A1 (de) * 1991-09-05 1993-03-10 NIPPON GASKET COMPANY Ltd. Metalldichtung sowie Herstellungsverfahren dazu
US5348315A (en) * 1991-07-17 1994-09-20 Nippon Gasket Co., Ltd. Metallic gasket
US5536024A (en) * 1993-12-01 1996-07-16 Ishikawa Gasket Co., Ltd. Metal gasket having sealing beads with different width and height
EP0874181A3 (de) * 1997-04-24 1999-10-13 Ishikawa Gasket Co. Ltd. Metalldichtung mit örtlich wärmebehandelter Wulst
EP1026427A3 (de) * 1999-02-01 2001-09-12 Ishikawa Gasket Co. Ltd. Mehrschichtige, metallische Flachdichtung mit verstellbarer Dicke
EP1138987A3 (de) * 2000-03-29 2003-10-22 Nippon Gasket Co., Ltd. Einschichtige Metalldichtung
EP1327800A3 (de) * 2002-01-09 2004-01-14 Ishikawa Gasket Co. Ltd. Metalldichtung mit Flanschbeschichtung und Verfahren zur Herstellung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3053544A (en) * 1958-10-24 1962-09-11 Chrysler Corp Gasket
EP0468526B1 (de) * 1990-07-26 1995-04-05 Taiho Kogyo Co., Ltd. Metalldichtung

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3053544A (en) * 1958-10-24 1962-09-11 Chrysler Corp Gasket
EP0468526B1 (de) * 1990-07-26 1995-04-05 Taiho Kogyo Co., Ltd. Metalldichtung

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5348315A (en) * 1991-07-17 1994-09-20 Nippon Gasket Co., Ltd. Metallic gasket
EP0528698A1 (de) * 1991-08-21 1993-02-24 NIPPON GASKET COMPANY Ltd. Metalldichtung und Verfahren zu deren Herstellung
US5310196A (en) * 1991-08-21 1994-05-10 Nippon Gasket Co., Ltd. Metallic gasket and method of manufacturing the same
EP0531076A1 (de) * 1991-09-05 1993-03-10 NIPPON GASKET COMPANY Ltd. Metalldichtung sowie Herstellungsverfahren dazu
US5294135A (en) * 1991-09-05 1994-03-15 Nippon Gasket Co., Ltd. Metal gasket and production method thereof
US5536024A (en) * 1993-12-01 1996-07-16 Ishikawa Gasket Co., Ltd. Metal gasket having sealing beads with different width and height
EP0874181A3 (de) * 1997-04-24 1999-10-13 Ishikawa Gasket Co. Ltd. Metalldichtung mit örtlich wärmebehandelter Wulst
EP1026427A3 (de) * 1999-02-01 2001-09-12 Ishikawa Gasket Co. Ltd. Mehrschichtige, metallische Flachdichtung mit verstellbarer Dicke
US6347801B1 (en) 1999-02-01 2002-02-19 Hironobu Nakamura Metal laminate gasket with thickness adjusting mechanism
EP1138987A3 (de) * 2000-03-29 2003-10-22 Nippon Gasket Co., Ltd. Einschichtige Metalldichtung
EP1327800A3 (de) * 2002-01-09 2004-01-14 Ishikawa Gasket Co. Ltd. Metalldichtung mit Flanschbeschichtung und Verfahren zur Herstellung
US6896271B2 (en) 2002-01-09 2005-05-24 Ishikawa Gasket Co., Ltd. Metal gasket with coating at flange

Also Published As

Publication number Publication date
DE69122838D1 (de) 1996-11-28
EP0486255A3 (en) 1992-12-02
DE486255T1 (de) 1992-10-15
EP0486255B1 (de) 1996-10-23
DE69122838T2 (de) 1997-04-03

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